Fluid flow regulator



R. A. M CALLUM FLUID FL OW REGULATOR July 7, 1953 2 Sheets-Sheet l Filed Nov. 15, 1944 4 /H/NMIMM/NM' [/l/l//l//l//l//l/l//l/J ///////////////A atty.

Patented July 7, 1953 UNITED STAT ES PATENT A o FFICE FLUIDFLOW REG'UI'ATOR"` Ro'bert' Anthony MeCallum, Michigan' City, Ijnd,

assignjor to Joy" Manufacturiiig Company; acor poration, of Pennsylvana Application November 13, 1944;SerialNo;-=563,253

My-in'ventiorr relates to appara-tus for regulating theflowof compressiblefluids and more particularly to apparatus-forregulating .the flow .of compressible fluids seas-:to maintain a subst'am tially constant veocity in -the-supply line in spite of moderate variations inpthepressuresor densities ofthefluidinthesupply li-ne. e

mostmotors whichuse-fluid as an operatw ing means, as for example ait air motor or internal combustion engine thespeedof the motor, when Operating at argii/en altitude, will-` be. determirred 'by: the Volume of fluid ;admittedto the motor perunit ot time. If it-is desiredmo regu1atethe speedz of themotor *this oa-n be done by regulatirg. the Volume otfluid admitted to the motor perunitaof time. In the past means have been available :for accurately regulatingithe flow- *of non-compressible fluidsr The present invention relates particularly to-means for controlling the flow of compressible fluids so as to maintain a reasonablyconsta'nt Volume of flow in spite of variations in pressure and density.

The common means of measuring fluid velocity are an orifice, a Pitot tube and a venturi. Each of these gives a pressure difierential (Ap) which is proportiohal to the square of the Velocity times the-density.

1) Ap KV d Where the density of a fluid is constant',` it is obviou's` that in order' to' maintain' a' constant velocity' of' floW"(V)' it is" only-necessary t'omaintain Ap' constant'. This can' be done -by a pressure, sensitive' device such as a piston or' diaphragm Working against' a spring or' weight. Howevenin order to maintain* a' constant VeIocity when the d'en'sit'y' of the'fluid varies', it' is' necessarythat Ap be made to* vary* in' proporti'on to the d'ensity'.` TransposingFormula '1` above From this it will be seen'--tl `at,- iri order to" hold the." veocit y' (V')'- constant, itis neessary' t-hol'd it is possibl'e to substi-tute absolutes pressu re for densit y; In: other' wordsa constant' velocity :may`

bemaintained by mazintaining PI P e b s aconstant. p

My invention acconphhges this result in a preferred embodiment tiiereofiby the provision of '24'Claims. o. 137 501? i two* mutualy oppositelyacting surfaces of ,un

equal areas cooper'atingthrough their' mutual opp'ositio in Operating a control vahe. The' smaller-of these areas issubjectd t theabs'olute .pressure in the supply' line d'eliverin'g' fluid fo'r admissio'n t`o'- theniotor' or other devi'ce which it is desired ;to control, while the larger', ot these" areas' is subecte'd to' sa .p`ressure equaI'to' the akisolute pressure jvustnientioned minus the pres sure drop across ari orificea Pitot tube ora Venturi. The differenti'alin `areas is created by means which either" does not introduce anyuricounterba'lanced' efie'ct resulting' from atmospherictpressure or which zwhollyor at least sub'- staitiall'y' avoid's" the introduction of effects re sulting from the subjection of surfaces;` during periods of' flow' regulatio'h, t'o' atmosp'heric" pressure. v

An object ,of my' inventio'n is" tdvprovide' afiimproved' mean'stfor reg'ulatingthe' flow of a com*- pressible A fluid so', asto maintain a substar'tially constant' Volume of flow'. Another obectof my'. i

to .provide improved means for controilirig the flow". of ai com'pressihle fluid,

incorporating; twodifferent .effective areas', one' actuated by the absolute' pressure of the fl'uid* and the other 'actuated'= bythe-absolute p'r'essur'e less -a pressure drop* produced as above', the forces so producedbalancing one anotherir such man-neras ,to control a regulati ng va'lve and therehy to maintain. a' substantially constant' e voiume oflflowi Still a..fu`rther object of my invention :is to provideimproved .means for' con'- trollir gtheflow of acompressible fluid comprsing" means for effe'cting` a pressure drop varying with the velocity of flow and means for subjecting. u nequal'roppositely acting areas to the absolute pressu-re' at one poi nt -in the-movn-gistream of'fluid and" to the absolutepressure at another point in saidmovi ng stream Where a pressure drop occurs, and means for 'varyingthe pressure drop at will; tion iswt'o providefor avaIve device whichis operative to controi the flow of a compressiblefluid improved: means for regulating -automatically. said val've. device` so as to 'maintaina--constant Volume of lflow rgadless .of variations in pressure and-density.- Still another: objectof my inyer tfon is-t gtprovide' improved control means= tfortajvalve which .regulates the flow of a= come Yet another object ofmy inven pressible fluid, said control means including an orifice or Venturi through Whichthe fluid fiows, an element having unequal opposite areas subjected to the pressures at opposite sides of the orifice or venturi, said element also having an area subjected to atmospheric pressure, and means for counterbalancing the effect of atmospheric pressure on said element. Other objects and advantages of my invention will hereinafter more fully appear.

In the accompanying drawings, in which for purposes of illustration two diagrammatic illustrations and two working embodiments of my invention have been shown for purposes of illustration,

Fig. 1 is a diagrammatic View for the purpose of illustrating the working principles of my invention from one aspect thereof.

Fig. 2 is another diagrammatic View for the purpose of illustrating the working principles of my invention in another embodiment.

Fig. 3 is a sectional View of a fluid flow regulating device constructed in accordance With one illustrative form of my invention.

Fig. 4 is a sectional view similar to Fig. 3, but showing parts in difierent positions.

Fig. 4A is a fragmentary View, showing a modification.

Fig. 5 is a sectional View showing another embodiment of the invention.

Referring first to Fig. 1, a pipe line l is adapted to be connected at one end thereof at 2 to the supply space of a fluid operated motor. Gaseous fluid is supplied to the pipe l from a connection 3 leading from a source of a gaseous Operating fluid, and flow from the line 3 is controlled by a balanced valve device 4 comp-rising a valve casin-g 5 in which a balanced piston valve E is reciprocable, the spaces at the opposite ends of said piston valve 6 being connected by a port 'l extending through the piston valve. The piston valve has an Operating rod. B and a counterbalancing rod 9 so that it is substantially completely balanced, and it Controls the flow through the casing 5 into which fluid passes from the line 3 through a port Ifl and from which fluid passes to the pipe I through a port ll.

For 'the purpose of controlling the position of the valve 6 and regulating the amount of fluid delivered to the motor through the line l, I have provided a di'Terential piston mechanism |5 herein diagrammatically illustrated and comprising a casing !E in which a differential piston Il is mounted. The piston has a projecting portion iii of substantial cross-sectional area extending through an opening !9 in one wall of the casing' 55; By reason of the presence of this portion [8 there are provided at the opposite sides of the piston l? unequal areas Let the cross-sectional area of the portion e be designated by A and the annular area at the leit end face of the piston ll' as Az. The area at the right hand end of the piston l' will then equal A+A2. The projecting portion [8 is connected by a link 20 and a lever mechanism 2l with the piston valve 4 24 and its connection with the lever 2! block out, as it were, entirelythe efiect-ofatmospheric pressure on the portion !8 and make it mathematically correct to consider the pressures acting on the area Az on the left hand end of the piston Il' and the pressures acting on the area at the right hand end of the piston IT (equal to the cumulative areas A--Az) as subjected to absolute pressures. The space 29 to the left of the piston ll is connected by a connection 30 with the conduit I, and the space 3! at the right hand side of the piston IT is connected by a conduit 32 to the line I at a point nearer the motor. Any suitable device for causing a pressure drop Varying with the flow through the pipe I may be provided, and I have illustrated this by the manually adjustable valve 33. It'will be understood that a Pitot tube arrangement, a venturi or an orifice could be substituted. Of course' the effect of the valve is that of a Variable orfice.

The principle of operation of the diagrammatically illustrated embodiment of the invention of Fig. l may now be readily understood. The pressure drop betweenthe point at which theconduit 30 opens into the line I and the point at which the Conduit 32 opens into the line l` where the pressure drop is measured, is Ap:K1V d` where Ap=the drop; K a constant, V vele-city;

Therefore, if

el P

is held constant, V will also be constant, and the speed of the motor to which fluid is supplied at 2 Will be constant.

It will be understood, as above indicated, that an evacuated chamber (this is shown in Fig. 2) may be used to eliminate the eflect of atmospheric pressure on the area which constitutes the difierential between the areas of the opposite sides of the piston l'l.

Now, it Will be noted that there is a force acting toward the left equal to (A--Az) P. There is also a pressure acting to the right equal to A2(P+AP) If the force towards the left exceeds the force towards the right the piston valve 6 will move in an opening direction and increase the fiow to the Conduit I and increase the differential in pressure AP. This Will result in movement of the piston Il to the right and a partial closing of the valve G. Conversely, if the force acting toward the right on the link 20 were the greater, the valve 6 would partially close, AP Would be reduced, and the force provided by the pressure acting in the chamber 31 Would move the piston ll toward the left and thereby tend to open the valve 6 further. Thus, in whichever direction movement of the piston ll takes place, there will be always a tendency to bring things to a balanced condition. Under such balanced conditions (A+A2)P:A2(P-[-AP). Transposing, A1P+A2P:A2P+A2AP`, and A1P:A2AP and Sinc Au and Azi e fixed enea& v

!h 2 is a constani'and thereforewill also be, heldconstant' It will be evident from tween the orifice and ,the motor (which can be avoided by. locating the motor veryjclose'to the. point. where 32 .enters the. conduit. l) then the displacement of the motor; and the speed of the m o must lso. be constant, and. t epurpqse of thismechanism, to wit, to hold the speed constant, will be realized.

If theorifice is fixed ata different opening, that is, if. the valve 3.3 which diagrammatically illustrates a, variable area orificehas its adjustment changed, the velocity in the throat, which is: thelvelocity of the fluid whichactuatesthe, motor, will remain the samebut theyolume of, fluid and the displacement will-stabilize ata different point, thus governing the motor ata different speed. And therefore, by changing the orifice setting (thesetting` of the valve33) it will be possible to goyern the the motor at any speed with-in its normal. running range. It, is within the contemplation of my invention that the valve 33 not only constitutes a device for adjusting theorifice size, but: also a .deyice movable wholls to interrupt theflowof motivefluidto the motor and thus to act as a stop` valve.-

Thereare many applications where, an absolutely constant speed is notdesi red. It iswell known, for example thatthe control of .a. n otor is more stableif thecontrol allows. themotor to slow dowrnsomewhat under increased load and vice Versa. such an efiect can be introduced. by increasing the yielding, force :acting on, the ;lever 2! until it is more than sufficientto counterbalance the force exertedby atmospheric pressure on the area A While azem pressur'e exists at the opposite side of this area. The -increased yielding 'force may be obtained by replacingth'e, spring 24 With aspring of greater strength, by providing adjustable abutment means for the spring-24, or by providing anotheryielding means acting with the spring 24. Assuming that. the spring 24 is replaced with aspring having a strength greater than that, needed` to balance the atmospheric pressure on, the area-Anbyan amount F, the balanceon the pisten H under this condition is As the load on themotor increases, I:: mustalso increase and decreasesr Thus decreases as also does the: fluid velocity: andthe speed (f-the motor. If F varieszwith the positionof .the supplyyalve and becomes-less' as the Valveis opened, this also tends to slow down-the motor with; increasd load. 'I'hesemodifications and otherswhich may be desirable forspecialappl-i tions do not in any Way -depart from the spirit-of the invention.

Referring next to 2, the mode of operation of this diagrammatic illustration of my inyention will 'be readily understood. In this- ;figure 'there issubstituted for the casing IS a diaphragm Qasing 46; which-is divided into two-chambersby -a flexible partition 41. The central portionof thepartition; ismade-rigid by opposi-te mate-elements 48-; 43 Betweenthe plate 48 and' the wall of theside of the. casing-46 more remote from the. va'lye mechanism 4'; there is arranged an evacuatedbellows 50, this being' fastened to thewall ds and to theplate' 48 so that the pressure in the chamber 52 at the left hand side of thediaphragm 41. canact only' on theportion of the diaphragm 41 and plate 48 outside the bellows We may consider theeffective-cross-sectional areasof the bellows 5.0 ;to correspond to the` area A. of the structure of Fig; 1, and that the annulararea surrounding the effective'circumfrenceoithe bellows 50 corresponds 'to' Aziri Fig; 1. The area at the right hand side of the be1 lows 4-1 is:substanti;al1y equal to; A+A2-,; the diameter of the, Operating rod 53 being kept so small 'as to be negl'igible. If it be desired to compensate for the cross-sectional area of this-rod' avery light, spring 54 may be applied to it, b-ut this is unimportanti with the area of the rod made sufliciently small. The connection of the chamber 52, is at' the approach side' to the adjusta-ble orifice provided by the valve device 33, and: the connection of the space55- at the-right of the diaphragm ,41 is` With the conduit l beyond the.: adjustableorifice33 It is unnecessary to describetthe mode of operation of'this embodiment oftheinvention' in detail,` as it does noti difier in 'basic principle-:from the mode' of' 'operation of-the structure of Fig. 1, the evacuated'bellows- 50. simply taking the place of the spring 24 and of the re:- ducedportion !8, the evacuation of'the-bellows' making .unnecessary the provision ofthe spring'. Becauseof, the small size` of the rod 5,3,it need not affect practically the equation applicable to the. first illustrated' form of the invention, and the, spring 54 is entirely unnecessary, for' example, with a one-e'ighth inch rod,for-th is spring-.Would then have to exert a. force of less than one-fifth of a pound, Also, sincethe pressure' differential AP' will be relatively small, the fact that the` cross-sectional area-of the rod is subtractedfrom A--Azwill be most negligibl'e.

` 'Turning now to' the more i'ully developed em bodi-ments of the-invention illustrated' on' the second sheet'of the drawings, the structure of Figs; 3 and 4 may be noted. Hereit Will be observed `that a'fiuid flow regulating device generally designated BI is'connected between aiconduitEZ leading' from a source of a gaseou'sfiuid supply not`showr', and a chamber 63,'which' may be a fluid supply line, or may' be the main suppl y connection toa motor not shown. The'regulating' device 6!" includes a block havinga bore. %which opens through' a surface, EflOf'thB block which surfaceforms a: boundaryior chambes; or line 53". Attached to,` the block sby screws( 68; is a. plate (9--c overing the open end ?of? he' o t.` e mate &e; isatra rsedsby op n n s 10 sti-'tha e-dm hmeendofl the bore 66 and the space to the right of the surface 67' are in communication with each other freely. Reciprocable within the bore 66 is a piston-type valve member 'H having stopped hores 12 and 'M extending axially therethrough. A rod '15 extends through the bores '52 and 14 and has an enlarged portion s received within the larger bore Ti, and the end portions of the rod are reciprocably guided in bores 'H and 18 extending respectively through the plate 69 and the left hand end of the block 65 at the inner end of the bore 36. A spring ao acts between the plate 53' and the enlarged portion 16 for pressing the latter against the shoulder at the junction of the bores 12 and 14 and thereby urges the piston ?i toward the inner (left hand) end of the bore 86. The strength of the spring 80 and its special functions will be later more fully described. Formed in the block 65 surrounding the bore 56 are longitudinaily spaced, annular grooves 82 and 83. Passage means 84 connects the groove 82 in communication with the conduit 52, and passage means 85 connects the grcove !33 in communication with the conduit 63. rhe piston 'H has formed in its periphery an annular groove 81 which is adapted to connect the grooves 82 and 83 in communication with each other when the piston is adjacent the inner end of the bore 66, and as the piston moves toward the right in the bore the communication between the grooves is restricted; and if the piston were to be moved to the extreme right hand end of the bore, communication would be cut ofi entirely. Extending longitudinally through the piston and opening into the groove 81' are passages '88, opening through the left hand end of the piston into the bore 6%. Extending towards the passage 85 and designed more or less to obstruct the latter, depending upon its adjustment, is an adjustable means, herein shown in the form of a bolt sl. This bolt is threaded into an opening 92 in the lock 55, and has its head 93 adapted to be moved toward or from the passage 85 to control the efiective fiow area at the mouth of the passage 85. Threaded on the outer end of the bolt is a nut EA engageable with the block 65 for looking the bolt in its different adjusted positions. Formed in the outer end of the bolt is a slot QS in which a screw driver blade may be received for the adjustment of the bolt.

The operation of the regulating device Bl will be clearly apparent from the description given; and its similarities to the diagrammatically illustrated structure of Fig. 1 may be readily appreciated. The cross sectional area of the portion of the rod 75 which extends into the opening 18 corresponds to the area A. The area Az is equal to the area of the annulus between the perlphery of the rod portion mentioned and the wall of the bore 65. The effective area at the right hand end of the valve H, including the right hand end of the rod 15 and the area of the portions of the end of the valve facing to the right within the bore 65 equals A-l-Az. 93 corresponds to 33, and the space in the passage 85, beyond the bolt head 93, and the space 53 correspond to the point of connection 'of the conduit 32 with the conduit I, while 'ID and the communication with the right hand end of the rod 75 co rrespond to 32. The space 84 and the space within the chamber BB on the supply side of the bolt head es correspond to the space in Conduit I ahead of valve 33, while 88 corresponds gener-ally to 36, through a portion of the area to the pressure in the space 63.

8 on which the pressure acts towards the right is not at the left hand end of the valve. The strength of the spring is such as to neutraiize the effect of atmospheric pressure on the exposed end of the plunger or rod 15.

Fluid delivered to the groove 82 from the conduit 62 will be conducted through the groove 81 in the piston 'H and the passage 85 to the fluid' supply line or motor inlet 63. There will be a drop in the fluid pressure between the groove 81 and the space 6-3, this drop depending on the degree of obstruction to the iiow of air determined by the position of the bolt head 93 and the absolute pressure of the fluid. The left hand end of the piston 'H and other areas cumulating with such end equals the area of an. annulus which is equal to the cross section of it minus the. cross section of ?2, and this area will be subjected to the pressure in the groove s'i through the passages 88. The right hand end of the piston will be subjected to the pressure in the supply line 63 through the passages w, while the end of the plunger '15 will be directly subjected This devic'e will operate then precisely as explained in connection with Fig. 1. If there is a tendency for an increased quantity of fluid to flow past the screw 93, there will be a greater reduction in the absolute pressure acting to move the piston 'H to the left than there is in the absolute pressure acting to move the piston 'H to the right, and so the piston 'H will move to the right and reduce the flow of gase'ous pressure to the space 63. If there is a tendency for the quantity of fluid fiowing past the flow controlling screw 93 to be diminished, then the'pressures at the right and left hand ends of the piston 'H will be more nearly equalized, and the piston 'H will move toward the left, increasing the Volume of fluid delivered. In Fig, 4A there is shown a modification in which a hand turned threaded stem in provided for moving the valve TI to closed position when this is desired, thus enabling the automatic control valve also to constitute a stop or throttle valve. It will be noted that spring 80 always tends to open valve H.

In the form of the inventicn shown in Fig. 5,. a conduit 62 opens into a chamber see formed in a' block lei, the chamber acting as a fluid supply space. A discharge passage !02 connects the chamber on in communication with an enlarged circular recess 183 in a face of the block and which is adapted to form a portion of a motor supply chamber supply line, or the like. Hereafter, IB3 will simply be referred to as the space !03.

Arranged in the space ::33 and overlying the discharge end of passage !52 is a valve plate isd having openings !05 formed therein. At the inner end of the space me, and adjacent the periphery of the latter, there is a narrow shoulder Hil, against which the plate me may seat, and. yet have a shallowspace 108 at its left hand side freely communicating with passage !02. The plate !04 has openings !JU extending through it, and through these openings cylindrical guides i i i extend. `'These guides have heads 2 at their right hand ends and threaded portions lis at their left hand ends, the latter threadedly received in bores |l4 formed in the block lili. Springs I !5, whose characteristics will later be described, surround the portions HI and engage the right hand side of the valve plate !94. Formed in the block in axial alinement with the passage !92 and of the same diameter as the latter at the left handend thereof, isgaboreu which ;a plunger lstaisaslidablyreceived. 'This plunger is :goonnected ::by a reducedpzportion Me, .extending through .the :passage !112 and throughan opening l2 0:in;th.e ;val-ve [04, .withthelatter. 'Ihe reduced portion: .l 'l szis-shouldered between :its ende, as at I;2,l `and;-the shoulder; engagesa the central porhub portion !25 ithreadedson the -redueedzportion lte tot the iright Lo. the shoulder 2:1 ;and lclamps, betmeen itand ;the .plate :I ML: alscreen 132.55. '1 The platermember ;2A.;is-.pr,ovided; with openings ;m which.communicatewiththe:emnin-es iwben it za ua to 4+ are -z .o a Q- 'Ql !04, because the holes jp ulsa :are ,on h le tsid oi ..he n e iii-i, b mea -.a c c e of li htly` .la g -df ameterthan h .-pli s r I8 d the pe hery ;o :the plate .ws-sis\ equa to Az. We. say sa ir le o s ight y larg :d amete tha ;the 1 lmger 1.! a. be a h .pre`s. eo thehole t. .l zthe e we dedhole of wlice t e umul v rea of; those s own th di a wouldabe, i r as d .i i meterto mp sa e or theia tbtin .all ircum tan es t pl te 1 04 wil hateitssize m d 19 hat it will have .anefi tive areapn :its ri h sideegua t AH-Aa and th f e tive (uneonte'ri ne ,i) area,,on its eit sid willbe A2. Th ea %mu d t e n riphei'y of .the valve pl t M se m i tly restr etedtopreventsubstant al inter enc With the ..o eration of the :dev ce throish leaka e .throu ia nular .space. henthe;d fierentia n pre snrebetween theile t and'ri' ht ;hand.. si des.of the n st ZSLM increas s, theh n enljlfi the yalre !514, etc. will move .to- Wardthe ri ht',obs ructingltheflow throughthe bassagegmz, and ,bythe diminution in' .the quan tits of 'fluid .fiwi thepressure d fi zential wil be imnshed andth `p ate !114 :will then .tend to mov ag'a to h le t, r on nine' th pas a Hi?. 'Whent e q a t y o ffiuidfiowin .tends to dimin s the 'difie ential inpressure .between th ophositesdesof the plate !04 will inturn diminsh and the ,plu er 18 w11. m0.Ve toward .the left, inoreasing the flow. The. provsion .ofthescree rd ce t e e ct ea o t o en s an consequently the velocity immediately adjacent to the openings. This reduees the possibility of 'the flow through theorificebeing-afiected -by extraneous' conditions; such as the position -of the valve. V

a resultof myinvention itwill be observed thattl -haveprovided an improveddevice-forregw dating' the fiow of gaseous pressure uids. It will ibe .noted :that the device operates ;automatically 'toregulate the flow of gaseous fluid in a manner ::to maintain .the s'peed of a motor-constant. 'It

will be observed that. means ;is .alsmprovided. for controlling the operation ;of amator so,as to maintain .the speed .of .the 1 atter ..constant at any' desired Value. 'The deviceoperates iso-:maintain the speed of the ;motors constant irrespeetiveiof changes in pressure .and density.

While I .have in this. application; specifically described ;two diagrammatic ;embodiments two more fully 'developed embodiments ;and a modification .of lone' of the latter, it :will .he innderstood thatthese embedimentsandthe modifieation ,are shown for 'purposes :of'illustration andethat the invention may .be furthermodified and embodied in various other embodimentswithout departing from .the spirit orthe :scope .of the: appencled claims.

What :I .claim-.as newuand 'desire to :secure ,by Letters 'Patent' is:

l. In a fiow regulating device, .in `eozrbination, means forming a passage for. conducting 'fluid having a supply end and a delivery end, ;means between said supply. .end and saiddelivery end for restricting flow and creating( adifferential -in pressure' between the' upstream andgdownstream sides of said fioW-restricting means; and a device for `controlling .the supply .of -fiuidto ;the supply end of said passage including :means `orming a Conduit leading to the supplyendof sad passage and an element -having a portion movable relative 'to said conduit to varythe flow: therethrough, said device having, for movingsaict element to vary the fiow,-an=area facing in -a direction to provide under the' action of-fluid pressure thereon a force tending to -move said` element -to provide for increased flow -past thesame, a smaller area 'facing in a direction to provide under the action of fluid pressurethereona-foree tending to move said element to diminishflow -past th same, and means -for eecting the `-subjection of-said 'first mentioned area-to the pressureat-the dovtnstream side of said fioW-restricting means and for subjecting said smaller area to thepres'sure at' 'the upstream side -of -said fioW-restrieting means, the -ratio of said first mentioned area` tosaidsnialler area being the same as the ratio of the absolute pressureat -theupstream side of saidiow-restrict ing means to the absolute pressui'e-at the downstream side of said' fiow-restrictingmeans.

` 2, Ina regulating device, in eombination, means pryidingapassage for conducting pressure fluid., means for rest ricting the flow of fluid through said passage, meansor supplyingpressure'fiuid to said passage, amovableelementhaving surfaces includingpppositely directed unequal pre'ssure areas, means-ronsubje'cting thesmaller of said -pressure areas to the absolute pressures at the intakeend of said passage, means -for subjeeting thej-largerof--said pressure areas to the absolute pressuresat thedischarge -end ofsaid passage, 'means :for precludingthe-exertion on said element of' any efiective element-moving force by any other *surfaeetheredf including yielding means aetingoppositely -to the direction of movement of -said-'element by 'the pressures acting on the smaller of-sa-id"pressure areas,-and valve means controlled bysaidelementior regulating the flow of fluid through saidf'fiuidsupply-means. r

i In;- a flow-regulating-device, in- -combination, means forrning a passage for conducting fluid having a supply end and adelivery end, means between said supply endand saiddelivery end 'for restricting-floW- and creating adifferential inpressure betweenthe-upstream andi downstream sides of said fiowerestrcting rmeans, land a .device .for

`controlling thesupply ofifluid to the supply end of said' passage including means forming a conduit leading to the supply end of said passage and an element having a portion movable relative to said conduit to vary the flow therethrough, said device having, for moving said element to vary the flow past the latter, an area facing in a direction to provide under the action of fluid pressure thereon a force tending to move said element to provide for increased flow past the same, a smaller area facing in a direction to provide under the action of fluid pressure thereon a force tending to move said element to diminish flow past the same and a third area facing in said last mentioned direction and with said smaller area equalling said first mentioned area, said first mentioned area being subjected to the pressure at the downstream side of said flowrestricting means and said smaller area subjected to the pressure at the upstream side of said flow-restricting means, and means for precluding said third mentioned area from influencing the movement of said device.

4. In a regulating device, in combination, means providing a passage for conducting pressure fluid, means for restricting the flow of fluid through said passage, means for supplying pressure fluid to said passage, a movable element having oppositely directed unequal pressure areas, means for subjecting the smaller of said pressure areas to the absolute pressures at the intake end of said passage, means for subjecting the larger of said pressure areas to the absolute pressures at the discharge end of said passage, means associated with said movable element presenting an area equal to the difference between said opposed areas and facing in the same direction as the smaller one thereof, means precluding the exertion by fluid pressure on said area on said element equal to the difference between said opposed areas of any force augmenting the force exerted by fluid pressure acting on said smaller pressure area, and valve means controlled by said element for regulating the flow of fluid through said fluid supply means, said element connected with said valve means and Operating on an increase in the pressure dierential acting thereon to move said valve means toward its closed position and eflect a reduction in the flow of fluid through said fluid supply means.

5. In a flow-regulating device, in combination, means forming a passage for conducting fluid having a supply end and a delivery end, means between said supply end and said delivery end for restricting flow and creating a differential in pressure between the upstream and downstream sides of said flow-restricting means, and a device for controlling the supply of fluid to the supply end of said passage including means forming a conduit leading to the supply end of said passage and an element having a portion movable relative to said conduit to vary the flow therethrough, said device having, for moving said element to vary the flow past the latter, an area facing in a direction to provide under the action of fluid pressure thereon a force tending to move said element to provide for increased flow past the same, a smaller area facing in a direction to provide under the action of fluid pressure thereon a force tending to move said element to diminish flow past the same and a ,third area facing in said last mentioned direction and with said smaller area equalling said first mentioned area, said first mentioned area subjected to the pressure at the downstream side of said flow-restricting means and said smaller area subjected to the pressure at the upstream side of said flow-restricting means, and means'for precluding said third mentioned area from influencing the movement of said device, the ratio of said first mentioned area to said smaller area being substantially the same as the ratio of the absolute nm sure at the upstream side of said flow-restricting means to the absolute pressure at the downstream side of said floW-restricting means.

6. In a regulating device, in combination, means providing a passage for conducting pressure fluid, manually adjustable means for restricting by varying amounts the flow of fluid through said passage, means for supplying pressure fluid to said passage, a movable element having oppositely directed unequal pressure areas, means for subjecting the smaller of said unequal areas to the absolute pressure at the upstream side of said flow-restrictng means, means for subjecting the other of said unequal areas to the absolute pressure at the downstream side of said flow-restricting means, said areas bearing a ratio to each other equal but inverse to the absolute pressures which act upon them, and valve means controlled by said element for regulating the flow of fluid through said fluid supply means, said element having another area in fixed relation thereto racing in the same direction as the smaller of said pressure areas and subjected to a substantially constant pressure and said element having associated therewith yielding means substantially exactly neutralizing the effect of the pressure on said another area.

7. In a regulating device, in combination, means providing a passage for conducting pressure fluid, means associated with said passage for producing a differential in pressure at different points along the same, means for supplying pressure fluid to said passage, means for controlling the 'flow of pressure fluid through said last mentioned means including a valve, means for deterinining the position of said valve including a member having two pressure areas facing in one direction and an oppositely directed pressure area equal to the sum of said two areas, means for subjecting one of said two areas to atmospheric pressure, means for connecting the other of said two areas to the high pressure side of said differential pressure producing means, means for subjecting said oppositely directed area to the pressure at the low pressure side of said diflerential pressure producing means, said pressure areas last mentioned being inversely proportional to the absolute pressures to which they are subjected, and means for subjecting said member to a force for balancing the pressure on the latter produced by atmospheric pressure.

8. In a regulating device, in combination, means providing a passage for conducting pressure fluid, means associated with said passage for producing a differential in pressure at different points along the same, means for supplyng pressure fluid to said passage, means for controlling the flow of pressure fluid through said last mentioned means including a valve, means for determining the position of said valve including a member having two pressure areas directed in one direction of movement of said valve member and an oppositely directed pressure area, means for subjecting one of said areas at the first mentioned end to atmospheric pressure, means for subjecting the others of said areas to said differentially related pressures, and means for subjecting said member to a force for balancing z :mem

13 the: pessune' on fihe 'latter mducedzhy mismo& phericpressure. e e e :9..naregulatingidevica in hambination meens providing a apassageor conductin g ispressne by -varying amounts :the fiov/ of fluid :tthnough said mpassage, means for` supplying pressune fluid .to said passage a mcvahle element &havingopposibely. directed nnequ'alpressure areas means for` subjecting sai d pressure areas to the:absolute pressres at the :opposte-sides f sa-id rest icbing means, said .areas hearing te eachot-her 'a ratio equa l but nve'se to-the absomte pressurest the epposite sides of=-said restrieting means sai'd e'lement having in fixed relati on the'reto andther for ;controlhng fchegsimply :@i sfi end: Qfssd assa e -smcludn ,m a condit leading to ?the supp y i sagetand ;an element-.mai in facingin a. directio iozptovide under: i p on, of ;fluid pressure thereon asfotce ien irg ita ;moi ze. saidselement. .to ;provid =for::ihcreased ::flow p st the same, asmaller areaiac ng in a,;dir 'on 'to provide under :the actionof fiud pressure'th a. :once tending to *moye;said;e1ementato.- dimin Sh flow past :the same andhihird area facirgjin said last mentioned direction andmibh saidwsmal ler are ieqalling said ;first-memionedarea, saidfrst mentioned. 4 area r being sbiectedio .ethe. :pressre at the rdownstream eside; ofsadflowsresbrictih means and-. said..sma11er areabeing subiehted :120. the essuteatzthe upstrteamjs'de `;ofsai-d :f1ow-. zestrictingmeans;;meansiforsbjeciingsaidthnd area toatmospherczpressure and means .for ;precluding said third mentioned area *from in fuencng `the :movement of .said ,device :includin resilient means counterhalancing jhe ;fame exetted `by atmospheric pressrehn. saidczmhird area, ;thejratio ;of .said :first 'muhamed-.enea. ;to saidsmaller area beingsuhstantial'ly zthesameas the ;ratio .of the( absolute .pressure at ;the ;upstream side oisaidvfiowrestriciing means; to; ;the .a-lose: lute pressure ,at ethe ..downsi'ream sidei'hereof.

. 1-3. FF-.he -combnation ,defined in .claim ;5 ;in which said'` fiow restricting means ,is ,moyable withsad device. i

.45. ;The ccmbinato definedfiinhciaime5 which :means ;is provided ;for .adiustably h'miting the movement hof; saidc element. I

. 117. Theiombinaton defined 'in claim .:5'-in which .said third area .is formed on .a reduced plunger moving #with said ele-ment.

218. 'The combination defined in claim 5, in which said first mentionedand smaller areas .are formed ;on a ;plate ;connected xto said ;elementand ,in "which said flowrestricting :means sis. ;carried byisaidxplate. e e e e 1:9. The combination 'defined in:c1aim 1,2, in whiehssaidfirst .mentioned :and smallerareas are 4 fol-.medon a plate connected ztosaideelement, :in

arranged between said connections for conducting fluid from the first to the second and for governing the flow from one to theother including means for providing a restriction such as to cause the existence upon the flow of a predetermined Volume in a unit of time past said restriction of a predetermined difference in pressure at the opposite sides of said restriction, valve means variably positionable to permit diferent volumes in a unit of time to flow through said conducting means, and means for'controlling the position of said valve means including an element having oppositely facing unequal areas and a surface exposed to ambient pressure, said surface equal to the difference between said unequal areas, and the product of the smaller of said unequal areas multiplied by the absolute pressure at the supply side of said restriction providing means being equal to the product of the opposed larger area multiplied by the absolute pressure at thedischarge side of said restriction providing means, when a predetermined flow past said restriction providing means is taking place, said element having associated therewith means for exerting thereon a force equal to the product of the area of said surface multiplied by the value in pounds absolute of the ambient pressure.

21. In a regulating device, in combination, means providing a connection for communication with a source of gaseous fluid under pressure, means providing a connection for communication with a motor, means between said connections providing a restriction such that a difierential in pressure exists at opposite sides of said restriction during fluid flow between said connections, an element having oppositely facing surfaces. one subjected to the pressure downstream of such restriction, and the other subjected to the pressure at the side of the restriction nearer the first mentioned connection, means movable with said element for rendering the eective area of said second mentioned surface suflciently less than the effective area of said first mentioned surface so that the ratio of said areas will be substantially the same as the inverse ratio of the absolute pressures at opposite sides of said restriction during the existence of a unform flow rate through said regulating device, means forming a valve moving with said element and movable by the latter to vary the flow between said connections, said element having movable therewith a further surface exposed to ambient pressure and equal in area, to the difference between the areas of said first mentioned surfaces, and means for subjecting said element to a pressure substantially equal to absolute ambient pressure multiplied by said third mentioned area, said last mentioned pressure directed oppositely to the force produced by ambient pressure on said area. e

22. In an apparatus of the class described, in combination, means providing a connection for communication with a source of gaseous fluid under pressure, means providing a 'connection for communication with a motor, and means arranged between said connections for conducting fluid from the first to the second and for governing the flow from one to the other including means for providing ,a restriction such as to cause the existence upon the flow of a predetermined Volume in a unit of time past said restriction of a predetermined difference in pressure at the opposite sides of said restriction, balanced valve means variably positionableto per mit different volumes per unit of time to flow through said conducting means, and means for controlling the position of said balanced valve means including an element having associated therewith means for providing on its oppositely racing surfaces effective areas respectively subjected to the pressure at the supply side and at the' discharge side of said means providing a restriction and respectively having the ratio of their areas inversely proportional to the pressures at the opposite sides of said restriction, said balanced valve means under the action of the fluid of which it controls the flow exerting no pressure in either of the directions in which said surfaces face.

23. In a' regulating device, in combination, means providing a bore, fluid supply means communicating with said bore at a point between the ends of the latter, fluid discharge means communicating with said bore at a point spaced longitudinally from said fluid means, said fluid discharge means having an intake end and a discharge end and, between said ends, a flow restricting device for causing a differential in pressure between the opposite sides thereof, means for restricting the flow of fluid from said fluid supply means through said bore to said fluid discharge means including a piston reciprocable in said bore and having oppositely directed unequal pressure areas, means for subjecting the smaller of said pressure areas to the absolute pressure at the intake end of said fluid discharge means, means for subjecting the larger of' said pressure areas to the absolute pressure at the discharge end of said fluid discharge means, the ratio of said areas to each other the same as but inverse to the ratio of the absolute pressures to which they are subjected, said piston having therein a groove for connecting said fluid supply and discharge means in communication with each other, said groove communicating with said fluid 'supply means in varying the degrees depending on the position of said piston.

24. In an apparatus of the class described,

in combination, means providing a connection for communication with a source of gaseous fluid under pressure, means providing a connection for communication with a motor, and means arranged between said connections for conducting fluid from the first to the second and for governing the flow from one to the other including means for providing a restriction such as to cause the existence upon the flow of a predetermined Volume in a unit of time past said restriction of a predetermined difference in pressure at the opposite sides of said restriction, valve means variably positionable to permit different volumes in a unit of time to flow through said conducting means, and means for controlling the position of said valve means including a chamber having therein an element having at its opposite sides opposed, equal, annular areas and at one side a central area, the annular area and the central area at said last mentioned side subjected to the pressure at the discharge side of said restriction providing means, and said equal opposite annular area subjected to the pressure at the supply side of said restriction providing means, said last mentioned side of said element having associated therewith a portion extending to the outside of said chamber and of like cross sectional area with said central area and subjected to ambient pressure, and means for exerting on said element, in the direction in which the pressure on the central area acts, a

17 force equal to the cross sectional area. of said Number portion multiplied by ambient pressure. 991541 1,699,676 ROBERT ANTHONY MCCALLUM. 1,993,527 2,069,022 References Cited in the file of this patent 2355337 UNITED STATES PATENTS 8J Number Name Date 598,935 Jewell Feb. 15, 1898 10 Number 750,752 Cole Jan. 26, 1904 325347 18 Name Date Plantinga May 9, 1911 Rush Jan. 22, 1929 Mars Mar. 5, 1935 Sisk Jan. 26, 1937 Kendrick Sept. .16, 1941 Haultain Oct. 14, 19 1 FOREIGN PATENTS Country Date Italy of 1935 

